This invention relates to tremolo devices such as those found on Stratocaster® style guitars and are disclosed in U.S. Pat. No. 2,741,146 issued to C. L. Fender on Apr. 10, 1956. The operation and shortcomings of this design were discussed in U.S. Pat. No. 6,943,284 issued to E. W. Didan on Apr. 14, 2005, and are reproduced here. Some reference numbers have been changed where they refer to the present invention.
“The bridge plate of the tremolo device is situated to pivot on an axis transverse to the direction of the strings. Bridge saddles located on the bridge plate engage the strings to create the intended change in string tension when the player moves the tremolo actuating arm. A counter spring is employed to oppose and counteract the pull of the strings on the bridge plate.
“A problem attendant to the use of such known tremolo devices arises with the breakage of a string. Because the tension of the strings is balanced by the above mentioned counter spring, loss of the force on one or more strings allows the counter spring to displace the bridge plate. This increases the tension on the remaining strings, causing them to go sharp. Thus, the instrument becomes unplayable.
“A second problem attendant to the use of such known tremolo devices arises when tuning. Because the tension of the strings is balanced by the above-mentioned counter-spring, change in force of the string being tuned causes the displacement of the bridge plate. This changes the tension on the remaining strings, causing them to go out of tune. In theory, an instrument with such a bridge can't be tuned. In practice, tuning may only be achieved by repeatedly tuning each successive string until converging on an acceptable tuning of all strings. Thus, the instrument is far more difficult to tune than one with an unmoveable or stabilized bridge.
“Referring now to the drawings in detail, wherein like reference numerals indicate like elements, there is seen in FIG. 1 a guitar designated generally by the reference numeral 1. As is conventional, the guitar 1 consists of a body 2 having a sounding board or face 8. Attached to the body 2 is a neck 3, having a nut 4 and means 5 for a retaining and adjusting the pitch of strings 6.
“A tremolo device, designated generally by the reference numeral 9, is secured to the face 8, and secures the bridge end of the strings 6. Referring now to FIG. 2, the tremolo device 9 includes a bridge plate 10.
“Anchor screws 14 secured to the body 2 provide pivot points for the bridge plate 10. In this regard, referring to FIG. 6 the bridge plate 10 is provided with holes 24, adapted to engage the anchor screws 14. The anchor screws 14 provide a hinge for the bridge plate 10 relative to the face 8.
“Referring now to FIG. 7, associated with the bridge plate 10 is an inertia block 11, which projects downwardly from the bridge plate 10 and extends into a recess 31 in the body 2 of the guitar 1. The strings 6 are secured by an inertia block 11.
“A tremolo actuating arm 16 is secured to the bridge plate 10. Also secured to the bridge plate 10 are bridge saddles 13, which engage the strings 6. Bridge saddles 13 have intonation screws 12 and elevation screws 15 to govern the length and height of each string respectively.
“It will now be seen that movement of the actuating arm 16 causes the bridge plate 10 to pivot relative to the anchor screws 14 and face 8. The bridge 9 causes such movement to vary the tension of all of the strings 6 to produce the desired tremolo effect.
“A counter-spring 28 is provided within recess 31 and coupled in tension to the body 2 and inertia block 11. Means 29 is provided to couple one end of the counter-spring 28 to an anchor screw 30, associated with the body 2.
“The foregoing structure is conventional and is found in the prior art, depicted in FIGS. 2 and 7.”